If you are saying that you are plugging a guitar cord into an input on an amp without the guitar on the other end and you are getting a hum or buzz with the volume turned up ; that is normal. If you are getting the same results with a guitar plugged in it means the ground wire to your output jack on your guitar is broken. Check your cord with a volt ohm meter for continuity on the tip on one end to the tip on the other end. Do this for the sleeve on one end to the other. If you were getting the buzz without a cable it would mean that your input jack in your amp has a broken ground connection. Hope this helps.
Also make sure you are using an INSTRUMENT cable and NOT a speaker extension cable. The cable should be labelled for instrument use. Speaker cables are often cheaper but NOT shielded for instrument use resulting in hum and buzz. Also the QUALITY of the instrument cables varies and some have poorer shielding.
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If you are saying that you are plugging a guitar cord into an input on an amp without the guitar on the other end and you are getting a hum or buzz with the volume turned up ; that is normal. If you are getting the same results with a guitar plugged in it means the ground wire to your output jack on your guitar is broken. Check your cord with a volt ohm meter for continuity on the tip on one end to the tip on the other end. Do this for the sleeve on one end to the other. If you were getting the buzz without a cable it would mean that your input jack in your amp has a broken ground connection. Hope this helps.
Also make sure you are using an INSTRUMENT cable and NOT a speaker extension cable. The cable should be labelled for instrument use. Speaker cables are often cheaper but NOT shielded for instrument use resulting in hum and buzz.
Also the QUALITY of the instrument cables varies and some have poorer shielding.